Syringe Inner Coating via Capillary Bridge for Uniform Gliding
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Solution Overview
Problem
Existing methods for coating pharmaceutical containers, such as syringes, struggle to achieve a homogeneous and uniform coating layer, leading to abrupt changes in gliding force during stopper movement, which impedes smooth administration of pharmaceutical compositions, and are difficult to scale for mass production.
Innovation Solution
A method involving a capillary bridge technique with a circumferential gap between the application body and the inner surface of the container, allowing the coating composition to form a thin, uniform film by pulling it over the surface like a blanket, reducing the tendency for larger accumulation and local stress maxima.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If spray coating methods are used to coat the inner surface of the container, then coating can be applied, but the coating layer becomes inhomogeneous and non-uniform
Solution Approach 1:
The patent introduces an application body as an intermediary carrier that holds the coating composition. This application body is inserted into the container and allows controlled transfer of coating material to the inner surface, replacing the uncontrolled spray method. The application body acts as a mediator between the coating composition and the container surface, ensuring uniform distribution.
Solution Approach 2:
The patent changes the physical parameters of the coating process by controlling the gap distance between the application body and the container inner surface. By maintaining a specific circumferential gap (not too close, not too far), the coating composition forms a capillary bridge that ensures uniform film thickness. This parameter control transforms the coating process from spray-based randomness to gap-controlled precision.
2Manufacturing precision
If a press-fit application body is used that contacts the inner surface directly, then coating can be deposited, but the coating composition accumulates locally creating stress maxima
Solution Approach 1:
The patent extracts the application body from direct contact with the container inner surface. By removing the press-fit configuration and introducing a circumferential gap, the application body no longer touches the surface directly. This extraction prevents local accumulation of coating material at contact points and eliminates the associated stress concentration problems.
Solution Approach 2:
The patent creates a capillary bridge that copies the function of direct contact without actual contact. The coating composition forms a meniscus bridge across the gap, transferring coating material uniformly along the container surface without the application body needing to touch the surface. This copying mechanism achieves uniform coating while avoiding the harmful effects of direct contact.
3Productivity
If simple production technology is used to facilitate mass production, then production efficiency increases, but coating quality and uniformity suffer
Solution Approach 1:
The patent employs a self-service coating mechanism where the application body, through its own movement and the capillary action of the coating composition, automatically achieves uniform coating distribution. The process does not require complex external control systems or multiple adjustment mechanisms - the gap geometry and material properties self-regulate the coating quality, enabling both simplicity and precision.
Solution Approach 2:
The patent replaces complex mechanical spray systems with a simpler capillary action-based coating mechanism. Instead of using pressurized spray nozzles, pumps, and complex delivery systems, the invention uses capillary forces in the gap to control coating flow. This substitution dramatically simplifies the production technology while maintaining or improving coating uniformity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method produces containers with superior film properties, ensuring uniform gliding properties of the stopper, reducing the risk of coating rub-off and potential contamination, particularly in pre-filled syringes, and facilitating mass production.
Implementation Method 1
the coating composition, which is applied to the application body, to touch or contact at least a part of the inner surface of the wall and the application body, thereby bridging the gap between the application body and the inner surface, forming a so-called capillary bridge
Data Source
AI summary
A method of making a coated container, e.g. a syringe. A method of making a container with a lubricant coating on an inner surface. This disclosure also relates to coated containers.